Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754334Ab3HBWTR (ORCPT ); Fri, 2 Aug 2013 18:19:17 -0400 Received: from shards.monkeyblade.net ([149.20.54.216]:42476 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752602Ab3HBWTQ (ORCPT ); Fri, 2 Aug 2013 18:19:16 -0400 Date: Fri, 02 Aug 2013 15:19:15 -0700 (PDT) Message-Id: <20130802.151915.1964036907997678424.davem@davemloft.net> To: klamm@yandex-team.ru Cc: eric.dumazet@gmail.com, raise.sail@gmail.com, ebiederm@xmission.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] net: check net.core.somaxconn sysctl values From: David Miller In-Reply-To: <1375454200-21303-1-git-send-email-klamm@yandex-team.ru> References: <20130801.141836.1104130035137318887.davem@davemloft.net> <1375454200-21303-1-git-send-email-klamm@yandex-team.ru> X-Mailer: Mew version 6.5 on Emacs 24.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.1 (shards.monkeyblade.net [0.0.0.0]); Fri, 02 Aug 2013 15:19:16 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1571 Lines: 42 From: Roman Gushchin Date: Fri, 2 Aug 2013 18:36:40 +0400 > It's possible to assign an invalid value to the net.core.somaxconn > sysctl variable, because there is no checks at all. > > The sk_max_ack_backlog field of the sock structure is defined as > unsigned short. Therefore, the backlog argument in inet_listen() > shouldn't exceed USHRT_MAX. The backlog argument in the listen() syscall > is truncated to the somaxconn value. So, the somaxconn value shouldn't > exceed 65535 (USHRT_MAX). > Also, negative values of somaxconn are meaningless. > > before: > $ sysctl -w net.core.somaxconn=256 > net.core.somaxconn = 256 > $ sysctl -w net.core.somaxconn=65536 > net.core.somaxconn = 65536 > $ sysctl -w net.core.somaxconn=-100 > net.core.somaxconn = -100 > > after: > $ sysctl -w net.core.somaxconn=256 > net.core.somaxconn = 256 > $ sysctl -w net.core.somaxconn=65536 > error: "Invalid argument" setting key "net.core.somaxconn" > $ sysctl -w net.core.somaxconn=-100 > error: "Invalid argument" setting key "net.core.somaxconn" > > Based on a prior patch from Changli Gao. > > Signed-off-by: Roman Gushchin > Reported-by: Changli Gao > Suggested-by: Eric Dumazet > Acked-by: Eric Dumazet Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/